Prevalence of adverse childhood experiences (ACEs) and the extent to which they relate to health among young adults (ages 18-25) returning home from jail is underexamined. To build on the growing literature examining associations between ACE exposure among young people involved with carceral systems and health, we (1) measured ACE prevalence and (2) explored associations between ACEs and health/well-being indicators among young adults experiencing reentry. Using a telephone survey on reentry experiences, participants completed an ACE screening, single-item responses on health and social indicators, and five-item responses on substance misuse. Fisher's exact tests and t tests compared sociodemographic and health-related factors by the levels of ACEs. Among the 85 participants, 66 (78%) reported four or more ACEs and 48 (56%) reported six or more ACEs, including divorced parents (n = 69, 81%), witnessing violence (n = 63, 74%), and household member incarceration (n = 60, 71%). Higher exposure to ACEs was associated with mental health diagnoses, psychiatric medication prescriptions, psychiatric hospitalizations, drug dependence, binge drinking, and cannabis misuse. High ACE exposure among young adults experiencing reentry portends worse mental health and high rates of substance use. Findings signify an opportunity to apply a trauma-focused developmental framework to support emerging adults during the crucial reentry period.